The Judas Cradle, also known as Judas chair, was a torture device invented in 16.th century Spain. During this torture, the criminal was first positioned in the waist harness above the sharp, pyramid-shaped seat. The point was then inserted into anus or vagina of the person, and then the person was slowly lowered by a system of ropes. The victims were usually naked, adding to the overall humiliation of the torture, and tortured by intense pressure and stretching of the orifice. Sometimes, various weights were tied to the legs, to dramatically increase the pain, and eventually tear muscular tissues of the orifice. This torture could last from a few hours to several days. Device was never washed, so the torture could often lead to painful infection or even death.
Similar to Judas’s Cradle, but much worse, spanish donkey(also known as wooden horse) was mostly used by the Spanish Inquisition during the Late Middle Ages. It was a sharply angled wooden device of triangular shape, pointing upward, mounted on a horse-leg like support poles. The naked victim was then made to sit on the the main board as if riding a horse, and various weights were attached to his or her feet, to increase the agony and prevent the victim from falling off. According to historical sources, the wedge occassionally sliced entirely through the victim as a result of too much weight being attached to his or her feet.
http://www.historyrundown.com/10-most-cruel-torture-devices-of-all-time/
In my opinion: The two devices have a very similar effect, but the first is much more cruel and more often caused by death.
A few pictures of Judas cradle, Judaswiege or veglia, its effectiveness!